Some implantable cardiac stimulation devices are equipped with multi-pole LV leads, i.e. leads provided with a set of electrodes sufficient to permit multi-site LV (MSLV) pacing. For such devices, it is desirable to determine optimal MSLV interelectrode pacing delays for use in delivering MSLV pacing. The MSLV interelectrode pacing delays can, for example, specify time delays between delivery of electrical pacing pulses at different sites within the LV or along different pacing vectors. The MSLV pulses may be coordinated with the delivery of pulses to the RV via a bipolar RV lead so as to improve cardiac hemodynamics. In particular, MSLV pacing may be coordinated with RV pacing to provide CRT pacing, which seeks to normalize asynchronous cardiac electrical activation and resultant asynchronous contractions associated with congestive heart failure (CHF) by delivering synchronized pacing stimulus to both ventricles. The RV and MSLV stimulus are synchronized so as to improve overall cardiac function. This may have the additional beneficial effect of reducing the susceptibility to life-threatening tachyarrhythmias.
Accordingly, some aspects of the invention are directed to providing systems and methods for determining preferred or optimal MSLV interelectrode pacing delays for use with MSLV pacing, particularly MSLV CRT. Other some aspects of the invention are directed to determining preferred or optimal combinations of LV electrodes or permutations of MSLV pacing vectors for use in delivering MSLV pacing using a multi-pole LV lead.